黒い街の鼓動 (Kuroi Machi no Kodō, Black City Heartbeat) is the twenty-third episode of Wolf's Rain. The episode aired in Japan on July 7th, 2003. Due to episodes 15, 16, 17, and 18 not being aired in the United States, the episode is sometimes considered to be the nineteenth episode by American fans. The episode aired in the United States on August 28th, 2004 as "Heartbeat of the Black City".

The four wolves go to Jaguara's City. They split up with Kiba and Tsume going to find information and a way into Jaguara's castle, while Hige and Toboe go look for food. Because of the tracker that Hige is unknowingly wearing, Jaguara knows of their presence, hoping they'll lead her to Paradise.